Creation of Spatial Charge Separation in Plasmas with Rigorously Charge-Conserving Local Electromagnetic Field Solvers

Charge-conserving local field solvers are widely used in today's electromagnetic plasma simulations. As in such codes the charge does not appear explicitly, the injection of new particles into the computational volume and their removal upon reaching the boundaries requires some cautiousness. While for quasineutral plasmas a particle injection in accordance with charge conservation can be realized quite easily, the injection of nonneutral plasmas with spatially separated electron and ion sources might lead to the emergence of unwanted divergences in the electric field. With a three-dimensional charge-conserving electromagnetic plasma simulation, we evaluate several injection schemes of nonneutral plasmas and present a method that rigorously respects conservation of charge and thus allows injection of nonneutral plasmas without producing unwanted divergences in the electric field.